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Abstracts
Workgroup: Frontiers in Disease Research
Mortality of the Pacific Oyster, Crassostrea gigas: identification and evaluation of multiple environmental stressors and methods to reduce associated mortalities
Principal Investigator(s):
Daniel Cheney, Pacific Shellfish Institute, cheneydp@compuserve.com
Co-Investigator(s):
Ralph Elston, Pacific Shellfish Institute
Carolyn Friedman and Gary Cherr, Univ. of California, Bodega Marine Laboratory
Christopher Langdon, Oregon State Univ., Hatfield Marine Science Center
Louis Burnett, Univ. of Charleston
Jonathan Davis, Taylor Resources, Inc.
Carolyn Friedman and Gary Cherr, Univ. of California, Bodega Marine Laboratory
Christopher Langdon, Oregon State Univ., Hatfield Marine Science Center
Louis Burnett, Univ. of Charleston
Jonathan Davis, Taylor Resources, Inc.
Funding Period: 10-1-01 to 9-30-03
During the first project year, we examined the interaction between survivorship, growth and stress responses of differing ploidy groups from commercial hatchery stocks and family lines from the Molluscan Broodstock Program (MBP) of Oregon State University, and planting time and height, and selected environmental parameters. To examine differential performance between oyster variety and family lines and planting period, oyster families outplanted during Fall 2000 and 2001 and Spring 2001 and 2002 at 2-3 sites in California, 3 sites in Washington (Spring only), and 1 site in Oregon (Spring 2002 only) were evaluated. Fall plants survived significantly more than did oysters planted in the spring (p<0.05) in California. In addition, two families (one commercial strain and MBP family 10-115) outperformed MBP family 10-116 (p<0.001) at all locations. Triploid oysters exhibited a differential rate of mortality, versus diploids from the same hatchery stocks. Mortalities varied between growout site and were manifested primarily in sub-adult animals. During the study period inter-annual variation in phytoplankton was more pronounced than spatial variation. While suspected harmful algal species were present in low to moderate concentrations throughout the study period, phytoplankton did not appear to be directly involved in oyster mortalities during 2002. However, repeated temperature and dissolved oxygen fluctuations were observed to be associated with oyster mortalities at the Washington and California study sites.
IMPACTS and/or BENEFITS:
This project was designed to aid in assessing genetic and physiological responses of Pacific oysters to environmental factors, culture locations and culture techniques. The principal benefits include development of disease-resistant broodstock and seed, and culture management tools to reduce mortalities (e.g. farm practices and mortality predictors, animal handling protocols under high stress conditions, and identification of environmental quality issues or concerns). Because significant variations in oyster survival, growth, condition, morphology, and physiological responses were found between differing families, ploides and varieties, research was being directed to providing growers with a suite of options to reduce summer mortality disease losses. These losses can presently exceed 50% of the marketable crop. This work was coordinated with on-going ODP funded herpes, and companion USDA MBP and NMFS-funded HAB research.
PROJECT PUBLICATIONS:
Friedman, C.S., Shamseldin, A., Olin, P.G., Robbins, T.T., and Cherr, G.N. In review. Investigation of a mass mortality of the Pacific oyster, Crassostrea gigas Thunberg, in Tomales Bay, California. Journal of Shellfish Research.
Hamdoun, Amro M., Daniel P. Cheney , and Gary N. Cherr. Phenotypic plasticity of HSP70 and HSP70 gene expression in the Pacific oyster (Crassostrea gigas): Implications for Resting Thermal Limits and Induction of Thermal Tolerance. Biological Bulletin. In preparation.
Hamdoun A M ; Cherr G. 2001. N. Phenotypic plasticity of HSP70 and HSP70 gene expression in the Pacific oyster (Crassostrea gigas): Implications for resting thermal limits and induction of thermal tolerance. American Zoologist. 41(6):1643-1644.
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